In an Long Term Evolution (LTE) or Long Term Evolution Advanced (LTE-A) system, a process in which User Equipment (UE) establishes a connection to a network is a random access process. The random access process of the UE is as follows: The UE sends a random access preamble to a base station by using a PRACH. After receiving the random access preamble, the base station replies to the UE with a random access response (RAR) by using a PDSCH. Then the UE sends a message 3 in the random access process by using a PUSCH. Finally, the base station replies to the UE with a contention resolution message.
In the random access process, the base station and the UE transmit messages by using a transmission time interval (TTI) of 1 ms as a basic transmission unit. To reduce a random access time, a shorter TTI may be used. However, limited by a channel environment of the UE or a scheduling status of the base station, in the random access process, if a TTI for transmitting messages is directly reduced, the UE cannot correctly receive a message, further resulting in an access failure. Therefore, a problem of long random access time still exists in the prior art.